This invention relates to air texturing of yarn and, more particularly, to improvements in a fluid jet apparatus used to texture the yarn.
Fluid jet apparatus for texturing yarn usually comprises a conically-tipped yarn guiding tube or needle for introducing yarn into the apparatus, a port for supplying pressurized fluid to a space surrounding the forward end of the needle and a nozzle having a conical entrance through which yarn and fluid leave the jet. Yarn is usually introduced into such a jet by moving the forward end of the yarn needle close to the converging entrance of the nozzle or vice-versa so that the flow of pressurized fluid is severely throttled between the two, producing an air pressure less than atmospheric at the forward end of the needle. This induces an inward flow of atmospheric air through the needle which will stringup the jet (i.e., draw an end of yarn into and through the jet). Although jets of this nature are generally satisfactory, stringup of fine denier yarns which have been wetted prior to texturing has been found to be difficult because the velocity of air through the needle is not sufficient to consistently overcome the drag on the filaments clinging to the walls of the yarn passages.